122 ANDREWS. 



EXPLANATION OF PLATE I. 



Fig. i. General appearance of young ovum and cell strings, floating in body 

 cavity. D. cuprea. Camera, Zeiss. 2. F. 



Fig. 2. Successive stages of growth of ova while floating in body cavity, g, ripe 

 ovum with green pigment about clear area, a. D. magna. X 250 diameter. 



Fig. 3. Various methods of branch formation in cell strings of D. magna. 



Fig. 4. Section of ripe ovum of D. magna from body cavity. Camera, Zeiss. 2. D. 

 <?, clear protoplasm. Green pigment remaining after hardening in Perenyi's fluid. 

 Haematoxylin and borax carmine stain. 



Fig. 5. Section of ovary of D. cuprea. Camera, Zeiss. 2. D. 



Fig. 6. Young cell string still attached to ovary. D. cuprea. Camera, Zeiss. 4. F. 



